Conducting glasses are indispensable in many optoelectronic applications, including flat-panel displays, solar electricity cells, diode lasers, and other optoelectronic devices, where they are used both as elements within the device optics and as a transport medium for electrons to move across a device surface. As such, the materials comprising conducting glasses (also called transparent conducting electrodes, or TCEs) require both high transparency and high conductivity for effective function. TCEs are used in a wide variety of specialty and electronic glass products, including both passive applications such as antistatic films, antireflective stacks, electromagnetic shielding, heat-efficient electrochemical windows, and electroluminescent lamps, and active applications such as flat panel displays, light emitting diodes, transparent membrane switches, touch screens, and thin film solar cells.
State-of-the-art for TCE's are based on metal oxides, which are not real conductors and have high sheet resistivities (>6, often 50 or 250 Ohms/□). Current solutions to the challenge of combining transparency with conductivity rely on coating glass with a thin layer of one of a variety of metal oxides, which are transparent and reasonably conductive. Indium Tin Oxide (ITO) and Fluorinated Tin Oxide (F:SnO2) are common materials used in TCE's. The drawback of this approach is that metal oxides are not proper conductors, with sheet resistance typically being at least 5 Ohms/□ for the most expensive products and often more than 60-200 Ohms/□ for lower-priced materials. As a result, there is currently a tradeoff when integrating lower-cost, high-resistivity conducting glasses into optoelectronic devices, with higher resistance translating into significant energy losses in several applications. The alternative strategy of employing significantly more expensive, incrementally more conductive glasses, often with still unsatisfying resistivity, leads to a limited adoption of otherwise market-competitive products.
Thus, expensive TCEs represent a bottleneck in the development of inexpensive optoelectronic products; in many cases, the TCEs are currently the primary cost contributor within a complex device (e.g. solar cells, LEDs).
Therefore, a need exists in the art for a relatively low cost, low resistivity transparent conducting electrode and a corresponding method for making it.